1. Field of the Invention
The invention relates to a method for sorting mailpieces according to their formats.
The invention also relates to a device suited for carrying out the method.
2. Related Technology
The method and the device are especially suited for processing incoming mail in a distribution center of a postal service provider.
This is where mailpieces that have been mailed by their senders in a mailbox of the postal service provider or that have been dropped off at a branch of the postal service provider or at another drop-off location typically arrive in an unsorted order to start with.
In order to prepare the further transport of the mailpieces to their destinations, the mailpieces are normally sorted in the distribution centers of the postal service provider according to their destinations or according to destination regions comprising several destinations. This is done in several sorting machines that are each configured for sorting mailpieces of a certain range of formats.
Therefore, it is necessary to first sort the mailpieces that have arrived at a distribution center according to mail classes and mail formats, so that they can be fed to the appropriate sorting machines. Moreover, the mailpieces have to be combined into ordered stacks so that they can be fed to the sorting machines without any problems.
The state of the art describes various methods and devices for sorting mailpieces according to their formats.
DE 201 21 614 U1, for example, discloses a sorting device having a conveying means with a plurality of crosswise connections on which eccentric elements are arranged that, together with adjacent crosswise connections, delimit passage openings. A rotational movement of the eccentric elements moves letters in a conveying direction, whereby letters with a small format fall through the passage openings, thus being sorted out of the mail stream.
This method has especially the drawback that the large-format mailpieces that occur in a much smaller number within the total mail volume are left in the mail stream, while the much higher number of small-format mailpieces are sorted out. As a result, the sorting is inefficient and moreover, the sorted-out majority of the letters that fall through the openings are subjected to considerable mechanical stress.
WO 03/035527 A1 describes a device for sorting and stacking mailpieces in which the mailpieces are fed via a conveyor belt to a sorting line at which the mailpieces that cannot be subsequently processed mechanically are sorted out. The other mailpieces move via the conveyor belt to a means where they are stacked in preparation for the subsequent processing steps. In order to process a large volume of mail, it can be provided that several sorting stations are set up from which the mailpieces that cannot be processed mechanically are first placed onto another conveyor belt that connects the sorting stations and they are then fed to the stacker via this conveyor belt.
The disclosed device has especially the drawback that the individual sorting stations have, a very complex structure with their own feed belts, slides and conveyor belts on which the sorting takes place and they take up a great deal of space, so that especially the processing of a large mail volume is ineffective.
German Published Examined Application DE 1 054 015 discloses a device for sorting mailpieces wherein the mailpieces are initially lying flat on a spiral conveying line on whose outer wall flat mailpieces move through slits to reach a conveying channel, whereas mailpieces of a greater thickness remain on the conveying means. Within the conveying channel, the flat mailpieces are set upright and conveyed along passage openings through which the mailpieces having a small height are diverted into secondary channels while the other mailpieces remain in the conveying channel.
The object of the invention is to create the capability for a reliable sorting of mailpieces according to mail classes and mail formats in the simplest possible manner, also in cases of a large mail volume.
According to the invention, this object is achieved by a method according to claim 1.
According to the invention, this object is also achieved by a device according to claim 9.
Advantageous refinements of the method and of the device are the subject matter of the subordinate claims.
In particular, the invention proposes that a method for sorting mailpieces according to their formats be carried out in such a way that mailpieces having at least two formats are fed by a first conveying means to a sorting line, that mailpieces having a first format are removed from the first conveying means in the area of the sorting line at several sorting stations arranged one after the other in the conveying direction of the first conveying means, and said mailpieces are fed to a second conveying means that runs in the area of the sorting line laterally next to the first conveying means, and that the mailpieces having other formats remain on the first conveying means.
The first format is preferably the format that occurs with the lowest frequency in a mail volume. In particular, the first format is preferably a large format in which the dimensions of the mailpieces exceed pre-specified values.
The method makes it possible for the mailpieces having formats that occur in small numbers to be removed from the first conveying means, while most of the mailpieces that have another format that differs from the first format remain on the first conveying means. In this manner, an especially fast and gentle sorting of the mailpieces is achieved.
The mailpieces with the other formats are, for example, small-format mailpieces a small format, which are present in much larger numbers in the usual mail volume than are mailpieces having the large format.
Moreover, the sorting is advantageously carried out at several sorting stations that are arranged one after the other along the first conveying means in the conveying direction, so that mailpieces having the first format that could not be removed from the first conveying means at a first sorting station are sorted out at one of the following sorting stations of the sorting line.
The sorting of the mailpieces at the sorting stations is thus not independent of each other but rather complementary. This results in a particularly reliable sorting which guarantees, to the greatest extent possible, that all of the mailpieces having the first format are removed from the first conveying means.
In an advantageous embodiment of the method, the mailpieces having the other formats are conveyed away from the sorting line by the first conveying means. This allows an especially simple construction of the device for carrying out the method.
The mailpieces are typically delivered to a distribution center of a postal service provider in containers, for example, in boxes or in bags. In an especially advantageous embodiment of the method according to the invention, the containers are emptied onto the first conveying means or onto another conveying means located upstream from the first conveying means. As a result, corresponding to the emptying of the containers, piles of mailpieces are created on the first conveying means and these are conveyed to the sorting line.
In an especially advantageous embodiment of the method, it is proposed that the first conveying means is stopped once such a pile has reached the sorting line. In this manner, sufficient time is available at the sorting line to recognize and sort out all of the mailpieces having the first format.
Advantageously, it can also be provided that the mailpieces are segregated before they reach the sorting line. In this manner, the piles are at least partially broken up so that an especially simple sorting at the sorting line is made possible and, in particular, a simple and fast recognition of mailpieces having the first format is possible.
In another preferred embodiment of the method, the mailpieces are accumulated on the first conveying means in the area of the sorting line so as to keep them in the area of the sorting line for a longer time.
This can be advantageously achieved in that the first conveying means ends in the downstream end area of the sorting line so that the mailpieces can be accumulated in front of the end section of the conveying means in a simple manner.
In an advantageous embodiment of the method, the mailpieces having the other formats that have been accumulated on the first conveying means in the area of the sorting line are fed to a third conveying means.
In the area of the sorting line, the third conveying means advantageously runs parallel to the first conveying means, and the small-format mailpieces are pushed off of the first conveying means onto the third conveying means once the mailpieces having the first format have been removed from the first conveying means.
After the sorting at the sorting line, at least the mailpieces with the other formats are segregated, set upright and stacked with aligned edges so that they can be fed to the subsequent automated processing steps.
Moreover, an advantageous refinement of the method is characterized in that the mailpieces having the first format are removed from the first conveying means and these mailpieces are fed to the second conveying means by means of a robot, at least at some of the sorting stations.
In this context, the term “robot” is to be understood in its broadest sense as a programmable manipulator. In particular, the robot is a reprogrammable multifunctional manipulator for carrying out variable programmable movement sequences as per the definition of the robot according to the specifications of the Robotic Institute of America.
The method according to the invention is thus advantageously suitable especially for sorting the mailpieces according to two formats. However, it can be further refined in a simple manner so that, in several sorting steps, sorting according to three or more formats is carried out in that those mailpieces that were taken away from the sorting line where the mailpieces having the first format are removed from the conveying means are fed, in the same manner, to another sorting line where the mailpieces having a second format are sorted out.
This can be carried out advantageously in that the mailpieces having the other formats are fed by the first conveying means to another sorting line where mailpieces having a second format are removed from the first conveying means and fed to a fourth conveying means. This, in turn, is preferably carried out at several sorting lines arranged one after the other along the first conveying means in the conveying direction.
The sorting at the other sorting line is preferably carried out in such a way that the format selected as the second format is the one that occurs with the lowest frequency within the mail volume having the other formats and that is consequently the format with the second-lowest frequency within the total mail volume. In this manner, the advantages of the method according to the invention in terms of fast and gentle sorting of the mailpieces are fully utilized.
In addition to the method, the invention also provides a device that is especially advantageously suited for carrying out the method.
The device for sorting mailpieces according to formats is especially characterized in that it comprises a first conveying means for feeding mailpieces having at least two formats to a sorting line with several sorting stations arranged one after the other along the first conveying means in the conveying direction thereof, and a second conveying means for receiving mailpieces having a first format runs in the area of the sorting line laterally next to the first conveying means on which the mailpieces with other formats remain.
The arrangement of the sorting stations at the sorting line makes it possible for the mailpieces having the first format that could not be removed from the first conveying means at a first sorting station to be removed at another sorting station and fed to the second conveying means.
The term conveying means is not to be construed in any limiting manner whatsoever within the scope of the invention but rather in its broadest sense. In particular, belt conveyors or containers being conveyed on a belt conveyor or on a roller conveyor are fundamentally suitable for use in the invention as the conveying means.
In an advantageous embodiment of the device, all of the sorting stations are arranged on a first side of the first conveying means. The second conveying means is advantageously arranged laterally on a second side of the first conveying means, opposite from the first side.
This arrangement allows a simple and ergonomic sorting of the mailpieces with which the mailpieces having the first format that have been removed from the first conveying means are fed via the first conveying means to the second conveying means.
In a preferred embodiment of the device, it is provided that a mechanism is present that can be operated from at least one sorting station in order to stop the first conveying means so that it can be stopped from the sorting station when large piles of mailpieces are fed to the sorting line. This ensures that sufficient time is available for the sorting of the mailpieces.
In another preferred embodiment, at the sorting line, the device has a mechanism for accumulating the fed mailpieces at the sorting line so that the retention time of the mailpieces at the sorting line is still sufficiently long, even if the first conveying means is not stopped.
The mechanism for accumulating the mailpieces is advantageously a downstream end section of the first conveying means.
Advantageously, it is also provided that, in the area of the sorting line, a third conveying means for receiving the mailpieces having the other formats runs parallel to the first conveying means. The mailpieces that have accumulated in front of the end section of the first conveying means can be fed to the third conveying means after the mailpieces having the first format have been sorted out.
In this context, a particularly space-saving and ergonomic approach is for the third conveying means to be arranged below the second conveying means. Advantageously, the second conveying means is offset upwards in terms of its height relative to the first conveying means. Moreover, the third conveying means is advantageously offset downwards in terms of its height relative to the first conveying means.
In another advantageous embodiment of the device, it is also provided that a robot is installed in at least one sorting station in for removing the large-format mailpieces from the first conveying means and for feeding these mailpieces to the second conveying means.
In order to sort mailpieces according to three or more formats in accordance with the above-mentioned method, preferably several devices configured according to the invention are arranged one after the other and joined to each other in such a way that the mailpieces that were not removed from the mail stream at a given device are fed to another device.
Moreover, in an advantageous embodiment of the invention, it is provided that, in the area of the sorting line, the second conveying means runs parallel to the first conveying means.
In another advantageous embodiment, it is provided that, in the area of the sorting line, the second conveying means runs along an ascending course relative to the first conveying means.
Additional advantages, special features and practical refinements of the invention will be understood from the description below of preferred embodiments making reference to the drawing figures.